Recent measurements and paradigms suggest that (1) the uptake of dissolved carbon and nitrate by phytoplankton may be greater than the Redfield ratio of 6.6 and (2) the oceans may be loosing nitrogen from an imbalance in the global rates of nitrogen fixation and denitrification. An analysis of concurrent ΔDIC/ΔNO3 depletion ratios within the Venezuelan and Peruvian upwelling ecosystems, indeed, suggests that values of 10.1--28.6 may pertain to these tropical eutrophic habitats. Nitrogen fixation may provide a Redfield balance in at least the former system, with 34--77% of the new production attributed to assimilation of N2. Independent confirmation of such new production on the Venezuelan shelf is provided by the interannual increases of H2S and DIC within the adjacent Cariaco Trench. ¿ American Geophysical Union 1996